碳化硅衍生碳的制备及其超级电容性能

以聚碳硅烷(PCS)为原料,通过不同温度高温热解制备碳化硅(Si C)前驱体,将得到的碳化硅前驱体在1 000℃条件下采用氯气刻蚀,成功制备了碳化硅衍生碳(Si C-CDCs)。采用X-射线衍射光谱(XRD)、拉曼光谱(Raman)、透射电子显微镜(TEM)和N2吸附-脱附法等表征方法,研究了热解温度对Si C前驱体及Si C-CDCs的物相、形貌、孔结构和分布的影响;并将制备的材料作为超级电容器的电极材料,测试了其电化学性能。结果表明:采用氯气刻蚀聚碳硅烷热解生成的Si C,可以得到具有较高比表面积和亚纳米孔(1 nm)的Si C-CDCs;Si C-CDCs用作超级电容器的电极材料,具有较高的比电容且在不同的电流密度下均表现出良好的电容性能。     

氢氧化镁-硼酸锌复合阻燃剂辅助制备产率高和电容性能优异的煤焦油沥青基多孔碳

以煤焦油沥青为前驱体,氢氧化镁-硼酸锌复合阻燃剂为助剂,直接在空气条件下高温碳化制备了煤沥青基多孔碳,并探究其电化学性能。得益于阻燃剂的阻燃协同其活化、掺杂功能化作用,得到了高产率(55.1%)、多原子(N、B、O)掺杂且具有分级多孔结构的多孔碳。将其作为超级电容器电极材料,在三电极体系中0.5 A·g^-1电流密度下比电容可达344 F·g^-1。此外,以制备的多孔碳和壳聚糖基氨基酸质子盐凝胶电解质组装的柔性对称电容器具有29.3 Wh·kg^-1的高能量密度,在50 000次循环后电容保持率为96.9%,且在-25~75℃温度区间内可正常工作,显示出宽的温度使用范围。     

超级电容器用炭/导电聚合物复合材料*

炭/导电聚合物复合材料是近年来发展起来应用于超级电容器的一种新型电极材料。炭材料与氧化物的复合材料,或者炭材料与导电聚合物的复合材料,能够将双电层电容与法拉第电容结合,既可提高超级电容器的比电容,改变其充放电电压,又可提高其循环性能。本文综述了近年来国内外各种炭材料,如活性炭,碳纳米管等与导电聚合物复合材料的研究进展,认为炭与导电聚合物的复合材料,尤其是性能优良的炭气凝胶,模板法制备的中孔炭,以及由金属或非金属碳化物与氯气等刻蚀剂反应制备的骨架炭与导电聚合物的复合材料是超级电容器电极材料研究的一个重要发展方向。     

碳基超级电容器电极材料的研究进展

超级电容器是近年迅速发展起来的一种新型储能元件,决定超级电容器性能的最重要因素是电极材料。碳材料以其比电容高、循环寿命长和资源丰富等优点,已经成为当前超级电容器电极材料的有力竞争者。用作超级电容器电极的碳材料主要包括活性炭、碳纳米管、石墨烯等。本文详细介绍了超级电容器用碳材料的特点、应用及发展状况,并指出制备具有大比表面积和高导电率的多孔碳是当前碳材料电极的主要研究方向。     

自活化乌拉草基多孔碳的制备和电化学性质

以乌拉草为原料,采用直接碳化方法,通过热解过程中前驱体自活化(即利用自身包含的活化剂实现分子内的化学活化),并经过必要的除杂过程制备了多孔碳材料Ula C-950-HF.测试了该多孔碳的电化学性质,并与以几种常见的生物质为原料制备的多孔碳材料及商用活性炭的电化学性质进行对比.结果表明,乌拉草基多孔碳材料Ula C-950-HF的电容值为113 F/g,经过4000次循环后,材料的电容值仅降低了4 F/g,显示出用作超级电容器电极材料的潜力.     

连续碳化硅原丝的成形基础研究北大核心CSCD

连续碳化硅纤维的原丝——聚碳硅烷纤维的成形是SiC纤维制备的关键技术之一,原丝品质的好坏对SiC纤维性能有重要影响。本文分析了聚碳硅烷和聚碳硅烷纤维的特点,并对聚碳硅烷的基本流变性质、粘弹性、聚碳硅烷的可纺性、纤维断裂机理和纺丝稳定性等研究进行了介绍。     

聚碳硅烷／纳米镍粉的热裂解

聚碳硅烷／纳米镍粉的热裂解王军＊宋永才冯春祥（国防科学技术大学材料工程与应用化学系长沙４１００７３）关键词聚碳硅烷，纳米材料，镍，热解，碳化硅纤维１９９６－０９－１７收稿，１９９６－１２－１３修回国家攻关计划和“８６３”高技术资助项目聚碳硅烷（ＰＣＳ...     

聚铝硅烷与聚碳硅烷共混先驱体制备SiC(Al)纤维

采用聚铝碳硅烷和聚碳硅烷共混制备含铝碳化硅的先驱体,并与直接合成得到的聚铝碳硅烷进行了比较.元素分析表明,共混法能够有效控制聚铝碳硅烷中的铝含量,且共混聚铝碳硅烷先驱体Si—H键含量更高.流变性能研究表明,共混获得的聚铝碳硅烷先驱体黏流活化能从255kJ/mol降至200kJ/mol,先驱体的可纺性提高,所以原纤维的平均直径从19μm降至12μm.预氧化后聚铝碳硅烷原纤维经1800℃一步烧成可得到致密的SiC(Al)纤维;XRD研究表明,纤维中的铝起到抑制碳化硅晶粒长大的作用.     

高性能碳基与过渡金属化合物基超级电容器电极材料的研究进展

超级电容器因其在电动车和便携式设备上巨大的应用潜力而受到广泛关注. 电极材料是超级电容器的关键组成部分, 决定了超级电容器性能的好坏. 近来大量研究以碳材料和过渡金属化合物作为电极材料. 然而, 碳材料电容值极小与过渡金属化合物导电性和稳定性差, 极大地限制了它们在超级电容器中的应用. 本综述重点介绍了我们课题组近年来在设计、可控制备及优化碳材料与过渡金属氧/氮化物电容性能的相关研究工作, 并讨论了材料构效关系及其调控机理. 最后对碳材料和过渡金属化合物作为电极材料的日后研究进行了展望.     

互通多孔碳/二氧化锰纳米复合材料的原位水热合成及电化学性能

以互通多孔碳（IPC）为载体,水热条件下在碳表面原位反应生成纳米结构的二氧化锰（MnO₂）,制备互通多孔碳/二氧化锰纳米（IPC/MnO₂）复合电极材料. 采用扫描电镜（SEM）,透射电镜（TEM）,X射线衍射（XRD）,热重分析（TGA）对其结构进行表征;采用循环伏安法、恒流充放电和交流阻抗对其电化学性能进行研究. 结果表明：生成的MnO₂均匀地负载在碳的表面,形成多层次结构,并且随着温度的升高IPC表面负载的MnO₂由纳米颗粒变为纳米片状结构;MnO₂纳米片具有典型的K-Birnessite 型晶体结构;复合物中MnO₂的含量约为34%（w）. 在100 ℃制备的IPC/MnO₂复合材料在三电极系统中最高比电容达到了411 F·g^-1;随着反应温度的升高,比容量先增长后基本保持不变. 以IPC/MnO₂为正极,活性炭（AC）为负极,1 mol·L^-1 Na₂SO₄溶液为电解液组装成IPC/MnO₂//AC 混合超级电容器,发现IPC/MnO₂电极的电容器其电位窗口从1 V扩展到1.8 V,容量可达86F·g^-1,且表现出良好的电容特性和大电流放电性能.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.